A network flow is a data stream that carries information between a source and a destination. As streaming video and other timing sensitive services become more ubiquitous, it has become important to recognize and prioritize traffic based on content of each network flow. Network flow identification can be used to support Quality of Service (QoS) tools, but also can be used to reveal malware and hacking attempts disguised as normal network traffic.
Flow Identification (FI) recognizes particular flows; traffic can then be adjusted as needed based on the traffic characteristics of a given flow. Deep packet Inspection (DPI) goes further. DPI is a form of packet filtering that examines the data and portions of the header as it passes through a router. It can not only identify a flow, but inspect the flow to detect security problems such as viruses, spam, and attempted intrusions.